Typically, exceptions in semiconductor processing are regular occurrences. Exceptions may be events that interrupt the normal control flows of the process control system. Examples of these exceptions may be new tape out (NTO), long-time-no-run (LTNR), periodic maintenance (PM), new chamber release, and the like. The impacts of exceptions may result in mismatched parameters of the process controllers from the actual state of the tools or processes. These impacts are generally unaccounted for in the modeling or are typically very difficult to model in the normal control algorithms.
In an attempt to remedy any mismatched parameters, engineers would typically enter control parameters after an exception occurred. The parameters that an engineer would enter were generally determined based on the engineer's experience and judgment. Because of this factor, results from processing after an exception could vary greatly. Also, there is usually some added variation that would occur between different engineers, particularly between an engineer with a high level of experience and a relatively junior engineer.
Further, the handling of the exception generally requires a relatively large amount of time when performed manually by engineers. A determination by an engineer of proper control parameters may take hours. This, in turn, may result in a large maintenance load and reduced productivity. Accordingly, there is a need in the art to overcome these deficiencies.